1. Field of the Invention
The present invention relates to a pivot with leaf springs. The pivot includes identical first and second members partially engaged in each other and rotatable relative to each other about a common axis, against the action of a return leaf spring which has first and second ends anchored in said first and second members, respectively.
2. Description of the Prior Art
Pivots of the above type are used in many applications where a device or member is mounted so that it can rotate through a small angle against a return force. Examples of such devices or members include measuring instrument pointers, oscillating mirrors, the platforms of scales, etc.
French patent No. 2 199 370 discloses a pivot of the above kind including two identical and axially aligned sleeves; each sleeve has an extension designed to be accommodated in a recessed portion of the other sleeve. Two crossed leaf springs elastically couple the two sleeves, which can turn relative to each other through a small angle and against the action of return forces exerted on the sleeves by the leaf springs. The leaf springs are anchored in axial grooves formed in the two sleeves.
The leaf springs can be welded into the grooves if the leaf springs and the sleeves are made of metal. However, the heating of the leaf springs during welding degrades their mechanical characteristics uncontrollably, especially when they are very thin, as is the case when the pivot is used to mount a delicate mechanical member such as a pointer, for example. This can falsify the equilibrium or rest position of the supported member and degrade the reliability of the assembly.
An adhesive can also be used to fix the leaf springs in the grooves. The physical and chemical characteristics of the adhesives unfortunately deteriorate over time or because of the environment (vacuum, extreme temperatures), especially in space.
A specific object of the present invention is to provide a pivot with flexible connections of the type described in the preamble to this description that is free of drawbacks referred to hereinabove.
The above object of the invention and others that will become apparent on reading the following description are achieved by a pivot with flexible connections including identical first and second members partly engaged in each other and rotatable relative to each other about a common axis against the action of a return leaf spring having first and second ends anchored in the first and second members, respectively.
In one embodiment of the invention, each of the ends of the leaf spring is wedged in an axial housing provided in one of the members, between a wall portion of the housing and a pair of superposed wedges gripped between another wall portion of the housing and the leaf spring.
In another embodiment of the present invention each of said leaf spring ends is shaped as a loop designed to be received in an axial housing of complementary shape in one of said members and a conical pin is forced inside said loop to expand it and wedge it in the housing.
An axially split cylindrical ring is advantageously slid into said looped end, between it and said conical pin.
Other features and advantages of the present invention will become apparent on reading the following description and examining the accompanying drawings.